Tool for u-bending of plated wire

ABSTRACT

A tool for U-bending plated wire that utilizes a compression type spring to bend the wire around a pin. The resilience of the spring when in contact with the wire contours the wire around the pin to form the U-bend without any damage to the wire or its coating.

United States Patent Rotondo et a]. [451 Oct. 10, 1972 4] TOOL FOR U-BENDING OF PLATED WIRE [56] References Cited [72] Inventors: Fortunato N. Rotondo, Concord; UNITED STATES PATENTS Emil Toledo, Natick' Leslie 1,309,663 7/1919 Smith ..140/87 Lawrence Needham Mass 3,189,058 6/1965 Petrasy ..140/104 [73] Assignee: The United States of America as represented by the Secretary of the Examiner L0We1lA- Larson N Attorney-R. S. Sciascia et a1. [22] Filed: June 15, 1971 PP N05 153,308 A tool for U-bending plated wire that utilizes a compression type spring to bend the wire around a pin. The resilience of the spring when in contact with the (g1. 140/1021,3 wire contours the wire around the p to form-the 58 Field oi'r'tjjfi'li'v' 555536152 102.5 bend with any damage the wire or mung 10 Claim, 2 Drawing Figures TOOL FOR U-BENDING OF PLATED WIRE BACKGROUND OF THE INVENTION l. Field of the Invention In the current state of technology, plated wire has found many uses, notably to be used in stacks. The stacks require U-bends in their fabrication which ordinarily weakens the wire or makes it more susceptible to gradual deterioration. This is especially true where the wire to be bent is plated wire such as used in memory units. The increased demand for plated wire stacks had made the need for a tool to accomplish U- bends more critical.

2. Description of the Prior Art I The current state-of-the-art to achieve U-bends in wire all seem to require application of heat to the wire. The heat is usually combined with pressure in the form of rolling around a mandrel or crimping around an abutment. The application of pressure in this form works the wire and makes it susceptible to fatigue or other deterioration. The further use of heat, for example in the range of 700 C, at the U-bend results in heat treating of the wire at this location which is an additional source of possible failure. The application of heat causes aging of certain wires, such as beryllium copper, which reduces its tensile strength and decreases its corrosion resistance. These standard methods of U-bending employing pressure and/or heat,

affect a large area of the wire, usually well away from the area of the bend.

' Statistics show that approximately ten per cent of all wire is destroyed by current U-bending techniques. Further, ten to twenty per cent of all stacks acceptable for use require replacement. Thus, current methods of forming U-bends in plated wire to be used for memory stacks are unsatisfactory and unacceptable due to the low percentage of stacks that survive the fabrication procedures and then perform well when in service.

SUMMARY OF THE INVENTION The invention is a relatively simple mechanical tool for forming U-bends in plated wires. A compressiontype spring of horseshoe configuration forms the wire around a pin without the need for heat or elevated pressures that might produce the effect of cold working the wire. This invention produces U-bends that are long lived since the metal has not been worked so as to prematurely age the wire or cause failure.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a plan view, in perspective, of the wire bending tool employing the subject invention.

FIG. 2 is an enlarged plan view, in perspective, of the spring used to form the wire into U-bends.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, the U-bending tool 8 is shown mounted on a supporting platform 10, with a length of plated wire 12 thereon. The platform is shown as a large plate, but it is understood that the tool 8 could be mounted on an assembly bench or as part of a larger fabricating installation utilizing the wire with the U-bends therein.

The tool 8 has a support base 14, upon which is mounted the bending mechanism 16 and a drive mechanism 18. The support base 14 is an elongated open rectangular frame having a pair of side rails 20 and a pair of end plates 22 attached thereto. A wire guide 24 is attached to the rails 20, near one end thereof and has an elongated oval opening 26 therethrough to receive the wire 12.

The bending mechanism 16 comprises a fixed member or block 28 and a movable member or slide 30.

The block 28 is attached to the rails 20 near the other end thereof to serve as an anvil or fixed member of the mechanism 16 and is bi-level in cross section. The top surface 32 of the block 28 is the same height above the rails 20 as the oval opening 26 in the wire guide 24 so that the plated wire 12 to be bent can be passed through the opening 26 and rest on the surface 32 of block 28. The block 28 is cut away to form a lower surface 34. The lower surface 34 has a pin 36 extending upward to a height substantially above the surface 32. Thus, the wire 12 can be looped around the pin 36 after passing through the opening 26 and over the top surface 32.

The slide 30 is a rectangular shaped block with a width to permit it to fit between and slide along the rails 20. At the end of the slide 30, adjacent the block 28, a portion of the lower side is cut away, forming an overhang or ledge 38. The ledge 38 is of sufficient heightto slide along the lower surface 34 of the block 38. The ledge 38 has an elongated U-shaped cutout 40, aligned with the pin 36, so that when the slide 30 is advanced into engagement with the block 28, the ledge will slide along the lower surface 34, and the cutout 40 will surround the pin 36, as shown in detail in FIG. 2.

A U-shaped spring 42 is adapted to fit in the cutout 40 and is fixed therein by spot welding or riveting at the base 44. The spring 42 has a diameter at the base 44 to conform to the cutout 40 and leave sufficient room between it and the pin 36 so as not to touch the wire 12. The legs 46 of the spring 42 are pinched together to leave a distance between them only slightly greater than the diameter of the pin 36. The free ends 48 of the spring 42 are rounded over to add to the resilience of the legs 46. Thus, when the slide 30 is advanced to engage block 28, the rounded ends 48 of the spring will engage the wire 12 around the pin 36 and expand and pass thereover. The legs 46 of the spring will then close around the pin 36 when it reaches the base portion 44. The resiliency of the spring leg 46 will then squeeze the wire 12 together, at the curve of the rounded ends 48, closer than the diameter of the pin 36, without application of high heat or pressure. As the slide 30 is withdrawn the rounded ends 48 will again squeeze the wire 12 up to the pin 36 and momentarily force the wire to conform to the contour of the pin as the spring passes thereby.

The drive mechanism 18 advances the slide 30, along the rails 20, into and out of engagement with block 28. The mechanism 18 is shown in the form of a torque wrench having a handle 50 and a gage 52 calibrated in inch-lbs. The shaft 54 is journalled for rotation in end plate 20 and a threaded portion 56 thereof extends forward between the rails 20. The threaded portion 56 is received in a threaded opening in the slide 30 to drive it along the rails 20 to engage the block 28.

this way the wire will not be galled or chaffed in any way by sliding contact with the parts of the tool. The drive mechanism 18 is then actuated by turning the handle 50 to advance the slide 30 into engagement with the block 28. As the slide 30 engages the block 28, the space between the ends 48 of the spring 42 causes the wire to be momentarily deformed to the contour of the pin 30 as the ends 48 pass by. The ends 48 then progress further along the wire 12 to squeeze it to a distance between strands less than the diameter of the pin 36. With the ledge 38 of the slide 30 fully engaged on the lower surface 34 of the block 28, the pin 36 is centered in the base 44, of the spring 42, and there is no compression or other galling of the wire 12 between the pin 36 and the spring 42. The only pressure exerted on the wire 12 is by the resilient legs 46 of the spring.

As the drive mechanism 18 is actuated to withdraw the slide 30 from engagement with the block 28 the rounded ends 48 of the spring 42, press the wire to the contour of the pin from the opposite direction from the engaging action. Thus, when fully disengaged, a U- bend has been formed in the wire 12 without application of heat or pressureon the wire.

The invention thus discloses a simple mechanical device to achieve U-bends in wire without in any way causing fatigue in the metal from heat or pressure. The drive mechanism has been shown as a torque-type handlebut it is obvious from the function thereof, that any suitable device producing linear movement would suffice.

Obviously many modifications and variations of the present invention are possible in the light of the above the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A tool for producing U-bends in wire, comprising:

a block having a pin extending therefrom;

a slide moveable into engagement with the block;

a cutout in one edge of the slide to surround the pin in spaced relation when the slide engages the block; and

a resilient member mounted in the cutout to engage a piece of wire looped around the pin to urge the wire to conform to the contour of the pin.

2. The device of claim 1, wherein the upper surface of the block has two levels with the pin extending upwardly from one edge thereof which is the lower of the two levels;

3. The device of claim 2, wherein the slide has a portion cut away from the lower surface-of the one edge thereof to permit the slide to overlay the lower surface of the one edge of the block.

4. The device of claim 1, wherein the cutout is generally U-shaped having an arcuate base and two parallel sides.

5. The device of claim 4, wherein the space between the parallel sides of the cutout is greater than the diameter of the pin plus twice the diameter of the wire.

6. The device of claim 5, wherein the resilient member is a generally U-shaped spring having an arcuate base and two free ends.

7. The device of claim 6, wherein the arcuate base of the spring generally conforms to the arcuate base of the cutout and is fixed thereto.

8. The device of claim 7, wherein the free ends of the spring are spaced apart a distance less'than the diameter of the pin plus twice the diameter of the wire.

9. The device of claim 8, wherein the free ends of the spring are arcuate in shape in an outwardly extending curve to present a curved surface to engage the pin and the wire thereon.

10. The device of claim 1, wherein means is provided to move the slide into engagement with the block. 

1. A tool for producing U-bends in wire, comprising: a block having a pin extending therefrom; a slide moveable into engagement with the block; a cutout in one edge of the slide to surround the pin in spaced relation when the slide engages the block; and a resilient member mounted in the cutout to engage a piece of wire looped around the pin to urge the wire to conform to the contour of the pin.
 2. The device of claim 1, wherein the upper surface of the block has two levels with the pin extending upwardly from one edge thereof which is the lower of the two levels.
 3. The device of claim 2, wherein the slide has a portion cut away from the lower surface of the one edge thereof to permit the slide to overlay the lower surface of the one edge of the block.
 4. The device of claim 1, wherein the cutout is generally U-shaped having an arcuate base and two parallel sides.
 5. The device of claim 4, wherein the space between the parallel sides of the cutout is greater than the diameter of the pin plus twice the diameter of the wire.
 6. The device of claim 5, wherein the resilient member is a generally U-shaped spring having an arcuate base and two free ends.
 7. The device of claim 6, wherein the arcuate base of the spring generally conforms to the arcuate base of the cutout and is fixed thereto.
 8. The device of claim 7, wherein the free ends of the spring are spaced apart a distance less than the diameter of the pin plus twice the diameter of the wire.
 9. The device of claim 8, wherein the free ends of the spring are arcuate in shape in an outwardly extending curve to present a curved surface to engage the pin and the wire thereon.
 10. The device of claim 1, wherein means is provided to move the slide into engagement with the block. 